How does resin polarity influence adhesion between WPC layers?

The adhesion between wood-plastic composite (WPC) layers is significantly influenced by the polarity of the resin used in their formulation. Resin polarity determines the interfacial compatibility between the polymer matrix and wood fibers, directly impacting bonding strength. Polar resins, such as those containing hydroxyl or carboxyl groups, exhibit stronger adhesion to polar wood surfaces due to hydrogen bonding and van der Waals forces. In contrast, non-polar resins like polypropylene require coupling agents or surface treatments to improve wettability and adhesion. Optimizing resin polarity enhances mechanical performance, reduces delamination risks, and ensures long-term durability in WPC applications. Understanding this relationship is crucial for selecting materials that balance cost, performance, and environmental resistance.